This order includes the species of cuckoos, geocuckoos and malcohas. They are terrestrial or arboreal birds with narrow beaks and long tails, and are found in forests on all continents except the poles. Their legs are zygodactyl, i.e. digits II and III are in front and opposite digits I and IV. This arrangement allows them to grip. Some species practise clutch parasitism, i.e. cuculiform females lay their eggs in the nests of other species who will take care of the clutch for them. They usually remove one egg from the clutch they are parasitising and replace it with their own. This prevents the parasitised female from discovering the subterfuge. Historically, Cuculiformes also included turacos, which were later classified in their own order of Musophagiformes.